Update dev dependency "nyc"

[mikeharder]

Our repo is currently using nyc@^14.0.0. A new major version nyc@15.0.0 was released on 12/20/2019:

https://github.com/istanbuljs/nyc/blob/master/CHANGELOG.md#1500-2019-12-20

I attempted to upgrade, and it mostly worked but tests failed on Windows with the following error:

Error: Cannot find module 'node-preload.js'

I believe this due to a bug in pnpm which impacts nyc: istanbuljs/nyc#1308. I tried the workaround suggested in that issue of adding --use-spawn-wrap to the nyc command line, but this failed on all platforms with the following error (when running tests for core-http):

Executing: "cross-env TS_NODE_FILES=true nyc --use-spawn-wrap mocha --require ts-node/register --timeout 50000 --reporter ../../../common/tools/mocha-multi-reporter.js --colors --exclude \"test/**/*.browser.ts\" \"test/**/*.ts\""

⨯ Unable to compile TypeScript:
.typings/karma.d.ts:1:24 - error TS7016: Could not find a declaration file for module 'karma'. 'sdk/core/core-http/node_modules/karma/lib/index.js' implicitly has an 'any' type.
  Try `npm install @types/karma` if it exists or add a new declaration (.d.ts) file containing `declare module 'karma';`

1 import * as karma from "karma";

I tried adding a reference to @types/karma as suggested, but tests still failed to load the types:

Executing: "cross-env TS_NODE_FILES=true nyc --use-spawn-wrap mocha --require ts-node/register --timeout 50000 --reporter ../../../common/tools/mocha-multi-reporter.js --colors --exclude \"test/**/*.browser.ts\" \"test/**/*.ts\""

Unable to require file: .typings\karma.d.ts
This is usually the result of a faulty configuration or import. Make sure there is a `.js`, `.json` or other executable extension with loader attached before `ts-node` available.

Draft PR: #9310

[jeremymeng]

Closing in favor of bot-auto-filed issue #19232

[ramya-rao-a]

This is now completed in #19248